1. Field of the Invention
The present invention relates to injecting machines and extruding machines used to manufacture molded products of fiber-reinforced resins, and particularly to a discharge device for discharging solids of a thermoplastic substance and fibers in a uniformly mixed state and a plasticizing device having this device.
2. Description of the Related Art
Conventionally, injection molding of fiber-reinforced thermoplastic resins is generally performed by methods including the following process steps:
(a) melting and kneading a thermoplastic resin and fibers in an extruding machine; PA1 (b) extruding the melted and kneaded material from the extruding machine to obtain fiber-reinforced resin pellets; PA1 (c) melting and kneading the fiber-reinforced resin pellets in an injecting machine; PA1 (d) injecting the melted and kneaded material from the injecting machine into a mold; and PA1 (e) cooling the melted and kneaded material to solidify it in the mold.
Japanese Patent Laying-Open No.4-286617 discloses an injection molding device having an extruding machine for kneading fiber and thermoplastic resin. The extruding machine in this device includes a cylinder having a first opening for supplying thermoplastic resin on the upstream end and a second opening for supplying fiber on the downstream end. The cylinder is equipped with a heater for heating the thermoplastic resin in the cylinder. The thermoplastic resin from the first opening is melted while being transferred toward the second opening by a screw type transferring means. Then fiber is added to the molten thermoplastic resin from the second opening and the fiber and thermoplastic resin are kneaded further downstream. The fiber-reinforced thermoplastic resin obtained this way is injected into a mold and molded. This method has the advantage that molded products of fiber-reinforced thermoplastic resin can be manufactured by almost the same procedure as common injection molding for thermoplastic resins except that fiber is supplied from the second opening provided in the cylinder of the extruding machine. In the case of this device, however, it is necessary to supply the thermoplastic resin and fiber from separated openings of the cylinder and to form a deep groove on the screw so that the fiber supplied from the second opening smoothly gets into the screw in the cylinder.
Japanese Patent Laying-Open No. 2-153714 discloses another device for injection-molding fiber-reinforced thermoplastic resins. This device, too, requires that the thermoplastic resin and fiber should be supplied from separated openings of a cylinder. This device further requires equipment for forcing the fiber into the cylinder at the opening for supplying the fiber.